CN110669233A

CN110669233A - Preparation method of PVA-based food packaging film with antioxidant and uvioresistant functions

Info

Publication number: CN110669233A
Application number: CN201810715180.XA
Authority: CN
Inventors: 李淑君; 翟迎香; 王江涛; 王昊; 宋涛; 胡蔚同
Original assignee: Northeast Forestry University
Current assignee: Northeast Forestry University
Priority date: 2018-07-03
Filing date: 2018-07-03
Publication date: 2020-01-10

Abstract

The invention discloses a preparation method of an antioxidant and uvioresistant PVA-based food packaging film, and aims to provide a safe and pollution-free antioxidant and uvioresistant green food packaging functional material. The preparation method of the invention comprises the following steps: preparing raw materials: the selected raw materials are rich in plant polyphenol, and the raw materials with larger blocks are crushed and sieved. (II) extracting plant polyphenol: extracting the prepared raw materials with solvent to obtain phenolic substances. (III) preparation of PVA solution: mixing PVA and water in proportion, heating and stirring until the PVA is completely dissolved to obtain a PVA solution. (IV) preparing the plant polyphenol/PVA composite membrane: dissolving plant polyphenol in a small amount of ethanol-water mixed solution at room temperature, mixing the solution and PVA solution in proportion, stirring uniformly to obtain plant polyphenol/PVA film liquid, and carrying out casting to obtain the plant polyphenol/PVA composite film. Compared with a pure PVA film, the antioxidant and uvioresistant performances of the plant polyphenol/PVA composite film prepared by the method are obviously improved. The antioxidant and uvioresistant functional PVA-based food packaging film has a good application prospect in the aspect of food packaging materials.

Description

Preparation method of PVA-based food packaging film with antioxidant and uvioresistant functions

Technical Field

The invention relates to a preparation method of a PVA (polyvinyl alcohol) -based food packaging film, in particular to a preparation method of an antioxidant and uvioresistant functional food packaging film.

Background

Food packaging is an important component of food products. Foods are susceptible to oxidation and spoilage. Antioxidant is a key function of active packaging materials, and antioxidant packaging materials are very helpful for prolonging the shelf life of food. Ultraviolet (UV) rays can also promote oxidative degradation of foods, and food packaging materials having oxidation and ultraviolet radiation resistance properties are very important. These natural products may be better used for food packaging materials, given the direct contact of certain packaging materials with food.

Plant polyphenols are known as natural antioxidants and also have uv-resistant properties. The plant polyphenol is the main component of the plant extract, is a green resource with rich and reproducible reserves, and is bound to become one of the most important resource treasuries for human utilization along with the gradual consumption of other disposable resources and the improvement of environmental protection requirements. Because plant polyphenol molecules contain various functional groups, the plant polyphenol molecules can be combined with other high molecular compounds in the forms of covalent bonds, hydrogen bonds and the like, so that the high molecular compounds can be synthesized or natural; and because the plant polyphenol not only has good biocompatibility and degradability, but also has various physiological activities, the plant polyphenol fully utilizes the physiological activities to prepare novel advanced materials, such as antioxidant and uvioresistant functional food packaging films.

Polyvinyl alcohol (PVA) is a highly polar water-soluble polymer prepared by hydrolysis polymerization of vinyl acetate, has good biocompatibility, hydrophilicity, thermal stability, film-forming property, emulsibility and the like, and is non-toxic, non-irritant and low in price. Polyvinyl alcohol (PVA) is a high-strength biodegradable synthetic material, has good tensile strength and light transmittance, but has no antioxidant and uvioresistant properties.

Disclosure of Invention

The invention aims to provide a preparation method of active food package, in particular to a preparation method of a safe pollution-free green food packaging film material with antioxidant and uvioresistant functions.

The preparation method of the PVA-based food packaging film with the functions of oxidation resistance and ultraviolet resistance is characterized by comprising the following steps: preparing raw materials: the selected raw materials are rich in plant polyphenols, such as folium Camelliae sinensis, cortex Pini, cortex Cercis chinensis folium Camelliae sinensis, and grape seed; in order to improve the leaching efficiency, the blocky raw materials are crushed and sieved, and the raw material particles used for extraction preferably have the particle size of 40-160 meshes. (II) extracting plant polyphenol: extracting the prepared raw materials with solvent to obtain phenolic substances. The extraction method of plant polyphenol can adopt ultrasonic wave auxiliary extraction, Soxhlet extraction, percolation method, soaking method extraction and the like; the extraction solvent of the plant polyphenol is one or more of water, methanol, ethanol, acetone and other polar solvents, preferably ethanol-water (5: 1-1: 5, v/v) mixed liquor; the feed liquid mass ratio of the plant polyphenol raw material to the extraction solvent is 1: 5-1: 100, preferably 1: 10-1: 30. (III) preparation of PVA solution: mixing PVA and water in a ratio of 1-10%, w/w, heating and stirring until PVA is completely dissolved to obtain PVA solution. (IV) preparing the plant polyphenol/PVA composite membrane: mixing the plant polyphenol extracting solution and the PVA solution according to the proportion (the mass ratio of polyphenol to PVA solid matter is 0.1-20%, preferably 0.5-2.0%), stirring uniformly to obtain plant polyphenol/PVA film liquid, and obtaining the plant polyphenol/PVA composite film by a casting method.

Compared with the prior art, the invention has the following advantages:

1. the plant polyphenol is the main component of the plant extract, is a green resource with rich reserves and reproducibility, and has the functions of oxidation resistance and ultraviolet resistance. Plant polyphenol molecules contain various functional groups, can be combined with other high molecular compounds in the forms of covalent bonds, hydrogen bonds and the like, and can be prepared into a novel functional material type intelligent package by fully utilizing the physiological activity of the plant polyphenol because the plant polyphenol not only has good biocompatibility and degradability, but also has various physiological activities;

2. the oxidation resistance and the ultraviolet resistance of the plant polyphenol/PVA composite membrane prepared by the method are obviously improved compared with those of a pure PVA membrane, and the oxidation resistance and the ultraviolet resistance are enhanced along with the increase of the concentration of the plant polyphenol.

Drawings

FIG. 1 shows that after the preparation of the larch bark polyphenol/PVA composite membrane is completed, a membrane sample is cut into a size of 1cm multiplied by 1cm, the membrane sample is placed into a sample bottle containing 10mL of distilled water, the sample bottle is placed on a magnetic stirrer at normal temperature and stirred for 30min, 1mL of the sample is taken and added into 4mL of PPH solution (150 mu mol/L), and the solution is uniformly shaken and mixed. Standing in dark place for 30min to allow radical scavenging reaction to occur sufficiently, and measuring absorbance at 517nm with TU-1901 double-beam ultraviolet-visible spectrophotometer.

FIG. 2 shows that after the preparation of the larch bark polyphenol/PVA composite film, the composite film is cut into a size of 2cm × 4cm, and the light transmittance (T%) of the prepared film is measured by a TU-1901 double-beam ultraviolet-visible spectrophotometer, wherein the scanning range is 200-800 nm. (0.25%, 0.50%, 1.00%, 2.00% are different larch bark polyphenol addition amounts, w/w)

Detailed Description

The first embodiment is as follows: taking 100-mesh larch bark, and leaching the 100-mesh larch bark with a 50% ethanol solution, wherein the material-liquid ratio is 1: and 20, performing ultrasonic treatment in an ultrasonic cleaning machine at normal temperature for 30min, then extracting for 2.5h in a constant temperature system at 55 ℃, performing suction filtration to remove precipitates, performing rotary evaporation on an extracting solution, and performing vacuum drying to obtain the larch bark polyphenol. 2.5g of PVA is weighed and added into an erlenmeyer flask, then 50mL of distilled water is added, and the erlenmeyer flask is placed in a constant temperature water bath at 90 ℃ and stirred until the PVA is completely dissolved, so as to obtain a 5% PVA solution. Uniformly mixing the larch bark polyphenol concentrated solution and the PVA solution according to the mass ratio of 2% of solid matters, pouring the mixture into a glass groove, and naturally drying at room temperature to obtain the PVA-based food packaging film with the functions of oxidation resistance and ultraviolet resistance.

The second embodiment is as follows: extracting 160-mesh tea leaves with 30% ethanol solution, wherein the material-liquid ratio is 1:30, soaking at normal temperature for 30min, filtering to remove precipitate, and rotary evaporating the extractive solution. Weighing 4g of PVA, adding the PVA into an erlenmeyer flask, adding 100mL of distilled water, placing the erlenmeyer flask in a constant-temperature water bath at 90 ℃, and stirring until the PVA is completely dissolved to obtain a 4% PVA solution. Uniformly mixing the tea polyphenol concentrated solution and the PVA solution according to the mass ratio of 1% of solid, pouring the mixture into a glass groove, and naturally drying at room temperature to obtain the PVA-based food packaging film with the functions of oxidation resistance and ultraviolet resistance.

The third concrete implementation mode: taking 80-mesh grape seeds, and leaching the grape seeds by using 70% ethanol solution, wherein the material-liquid ratio is 1:10, performing ultrasonic treatment in an ultrasonic cleaning machine at normal temperature for 30min, then extracting in a constant temperature system at 55 ℃ for 2.5h, performing suction filtration to remove precipitates, and performing rotary evaporation to concentrate the extracting solution. 1g of PVA was weighed, and 50mL of distilled water was added thereto, followed by heating and stirring until the PVA was completely dissolved, to thereby obtain a 2% PVA solution. Uniformly mixing the grape seed polyphenol concentrated solution and the PVA solution according to the mass ratio of 5% of solid matters, pouring the mixture into a glass groove, and naturally drying at room temperature to obtain the PVA-based food packaging film with the functions of oxidation resistance and ultraviolet resistance.

Claims

1. A preparation method of an antioxidant and uvioresistant functional PVA-based food packaging film is characterized by comprising the following steps: preparing raw materials: the selected raw materials are rich in plant polyphenol, and the raw materials with larger blocks are crushed and sieved. (II) extracting plant polyphenol: extracting the prepared raw materials with solvent to obtain phenolic substances. (III) preparation of PVA solution: weighing 2.5-3.0g of PVA, adding into an erlenmeyer flask, adding 50-70mL of distilled water, placing the erlenmeyer flask into a constant-temperature water bath at 80-90 ℃, and stirring until the PVA is completely dissolved to obtain a PVA solution. (IV) preparing the plant polyphenol/PVA composite membrane: dissolving plant polyphenol in a small amount of ethanol-water mixed solution at room temperature, mixing the solution with PVA solution, stirring uniformly to obtain plant polyphenol/PVA film liquid, and naturally drying at room temperature to obtain the plant polyphenol/PVA composite film.

2. The method for preparing PVA based food packaging film with antioxidant and uvioresistant functions as claimed in claim 1, wherein the raw material in step (one) is rich in plant polyphenol, such as tea, larch bark, black wattle bark, grape seed, etc.

3. The method for preparing PVA based food packaging film with antioxidant and uvioresistant functions as claimed in claim 1, wherein the larger lump material in step (one) is crushed and sieved, and the particle size of the extracted material is preferably 40-160 mesh for improving extraction efficiency.

4. The method for preparing PVA based food packaging film with antioxidant and uvioresistant functions as claimed in claim 1, wherein the extraction method in step (II) is ultrasonic assisted extraction, Soxhlet extraction, percolation, soaking extraction, etc.

5. The preparation method of the PVA based food packaging film with antioxidant and uvioresistant functions according to claim 1, wherein in the step (II), the plant polyphenol is extracted, wherein the solvent is one or more of polar solvents such as water, methanol, ethanol, acetone and the like, and is preferably an ethanol-water (5: 1-1: 5, v/v) mixed solution.

6. The preparation method of the PVA based food packaging film with antioxidant and uvioresistant functions according to claim 1, characterized in that the preparation of the (IV) plant polyphenol/PVA composite film is carried out, wherein the mass ratio of the plant polyphenol to the PVA solid matter is 0.1-20%, preferably 0.5-2.0%.